要创建额外的小按钮，请使用.btn-xs类。
您可以尝试运行以下代码以在Bootstrap中实现btn-xs类-
<!DOCTYPE html> <html> <head> <title>Bootstrap Example</title> <meta name = "viewport" content = "width = device-width, initial-scale = 1"> <link rel = "stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css"> <script src = "https://cdn.staticfile.org/jquery/3.3.1/jquery.min.js"></script> <script src = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script> </head> <body> <p>The following are extra small buttons:</p> <button type = "button" class = "btn btn-primary btn-xs"> Extra small Primary button </button> <button type = "button" class = "btn btn-default btn-xs"> Extra small button </button> </body> </html>